Biomedical subjects

J D Marco

Publications and source records attributed to J D Marco.

At least 19 recordsLinked to original sources

PubMed2005

Metal concentrations, foraging distances, and fledging success of great blue herons nesting along the Hanford Reach of the Columbia River.

An ecological risk assessment of the spatial distribution of metal concentrations along the Hanford Reach of the free-flowing Columbia River in southcentral Washington, identified great blue herons, Ardea herodias, at potential risk through the ingestion of contaminated riverine biota, especially fish. We measured metal concentrations in livers of pre-flight herons from the Hanford Reach and excrement samples taken from the same nests. Nests were distributed among three colonies situated upstream and downstream from nine retired plutonium production reactors along the river where metals in reactor coolant waters had been released directly into the river or disposed to shoreline retention basins and ditches. Distances traveled by parent herons to foraging areas along the river shore were determined by visually tracking parent birds as they flew from nests to upriver and downriver foraging sites. Foraging flight distances varied between colonies with mean distances ranging between 0.7 and 3.1 km. Cadmium, Cr, and Pb concentrations were higher in excrement than in the livers of pre-flight herons but the opposite was noted for Cu, Hg, and Zn. Highest metal concentrations of Cr, Cu, Zn, Cd, and Pb, were measured in excrement taken from heron nests at the colony located upstream from all reactors. These results were consistent with metal concentrations reported in river sediment from the same regions, indicating excrement from the heron nests may be a useful indicator of dietary uptake of metals by herons. Fledging success and eggshell thickness measurements were used as an index of health of the local heron population. The results indicate that the reproductive health of great blue herons nesting along the Hanford Reach is among the highest reported in the continental United States.

Animals↗

PubMed2002

Canine infection and the possible role of dogs in the transmission of American tegumentary leishmaniosis in Salta, Argentina.

Some Leishmania species affect humans in two principal forms: visceral and cutaneous leishmaniosis (CL). Several studies have identified dogs as the main reservoirs of the visceral leishmaniosis (VL) caused by Leishmania infantum. The purpose of this work was to carry out a survey of the canine population associated with human cases of American tegumentary leishmaniosis (ATL), in order to establish the clinical, parasitological, serological and immunological characteristics of the canine disease, in an endemic region for both ATL and Chagas' disease in the province of Salta, in northwestern Argentina. Two hundred and eight dogs from the endemic area were examined and 41 (19.7%) of them presented lesions compatible with leishmaniosis. In order to investigate the presence of antibodies against Leishmania spp. and Trypanosoma cruzi, sera were screened by ELISA using two complex antigens from these parasites and, because of cross-reactions between them, a specific antigen for diagnosis of T. cruzi infection. Sixty-two (29.8%) of 208 dogs were positive for the complex antigen F45 from Leishmania and 50 (24%) were positive for the complex antigen F105 from T. cruzi. Nine dogs (4.3%) were positive for the specific Ag163B6-cruzipain suggesting that these dogs were truly infected with T. cruzi. Furthermore, three of these nine dogs presented Leishmania sp. in their skin lesions and therefore were considered as infected by both, T. cruzi and Leishmania parasites. The prevalence of Leishmania infection detected by lesions and/or positive serology was 27.4% (57/208). On the basis of previous observations regarding the clustered appearance of human ATL, the dog population was divided into two groups: zone A, dogs living within a 100 m radius from houses with human cases, and zone B, dogs living beyond this limit. The prevalence of ATL in dogs was significantly higher in zone A (34.6%) than in zone B (7.3%), suggesting a strong correlation between canine and human cases. The average time required for a parasitological diagnosis by microscopy was six times longer for dog samples than human ones, and the average number of parasites per 100 microscopic fields was 14-fold lower in canine samples. The high prevalence of Leishmania infection and the close association with human cases, demonstrated that dogs are a very susceptible host for Leishmania infection, but the scarcity of parasites in their lesions suggests that they may not be the main reservoir of the parasite in this endemic area.

Animals↗

PubMed2001

Force of infection and evolution of lesions of canine tegumentary leishmaniasis in northwestern Argentina.

A clinical-serological follow-up was carried out in a canine population in endemic foci of Leishmania braziliensis spread in northwestern Argentina. Each dog was studied in at least two visits, 309+/-15 days (X+/-SE) apart. Some initially healthy dogs (n=52) developed seroconversion or lesions. The clinical evolution of the disease in dogs resembles in many aspects the human disease. Similarities include the long duration of most ulcers with occasional healing or appearance of new ones and the late appearance of erosive snout lesions in some animals. Yearly incidence rates of 22.7% for seroconversion and of 13.5% for disease were calculated as indicators of the force of infection by this parasite upon the canine population.

Animals↗

PubMed1991

Pathologic bronchial vasculature in a case of massive hemoptysis due to chronic bronchitis.

The cause of bleeding in a patient with recurrent massive hemoptysis was not apparent after bronchoscopy and gross examination of the lobectomy specimen. Histologic submission of all major bronchi uncovered dilated, tortuous bronchial arteries just below the bronchial mucosa with sites of both current and healing arterial rupture. This bronchial arterial abnormality is common to several chronic pulmonary diseases, but is rarely diagnosed as a cause of massive hemoptysis. Careful pathologic examination of major bronchi in the setting of hemoptysis of unknown causation is recommended.

Aged↗

PubMed1989

Determinants of homologous blood usage utilizing autologous platelet-rich plasma in cardiac operations.

The present study evaluated (1) the influence of the collection of autologous platelet-rich plasma intraoperatively in addition to intraoperative autotransfusion on homologous blood usage and bleeding in cardiac operations; (2) the influence of age, sex, body surface area, type of operation, and reoperations on homologous blood usage and bleeding in cardiac operations utilizing intraoperative autotransfusion and autologous platelet-rich plasma collected intraoperatively; and (3) the influence of the preoperative administration of aspirin, Persantine (dipyridamole), heparin sodium, thrombolytic agents, Coumadin (crystalline warfarin sodium), and nonsteroid, antiinflammatory drugs on homologous blood usage and bleeding in cardiac operations utilizing intraoperative autotransfusion and autologous platelet-rich plasma collected intraoperatively. The results demonstrated a decrease in homologous blood use and bleeding when autologous platelet-rich plasma is collected in addition to the use of intraoperative autotransfusion. All of the patient and procedural variables influenced homologous blood usage and bleeding to some extent. Only the thrombolytic agents affected blood usage by increasing homologous plasma usage. All other drugs evaluated did not influence blood utilization or the amount of bleeding intraoperatively or postoperatively.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed1988

Autologous platelet-rich plasma in cardiac surgery: effect on intraoperative and postoperative transfusion requirements.

The Southern Arizona Red Cross Blood program, in conjunction with participating hospitals and cardiac surgeons, evaluated the effect of a program to harvest autologous platelet-rich plasma (PRP) from patients immediately prior to undergoing cardiopulmonary bypass surgery. The PRP was transfused back to the patient after heparin neutralization was achieved at the completion of cardiopulmonary bypass. The effect of this autologous PRP product on homologous plasma and platelet usage was examined. The study demonstrates a significant decrease in homologous plasma and platelet usage when autologous PRP is used in cardiac surgery.

Blood Transfusion↗

PubMed1988

Intraoperative autotransfusion in cardiac operations. Effect on intraoperative and postoperative transfusion requirements.

The Southern Arizona Regional Red Cross Blood Program, in cooperation with two cardiac surgery groups, examined the effect of intraoperative autotransfusion on red cell, plasma, and platelet usage during and after cardiac operations. The study evaluated whether intraoperative autotransfusion influenced intraoperative or postoperative blood usage and whether regular use was more effective than selective use. The study demonstrated that intraoperative autotransfusion reduces intraoperative and postoperative blood use and that regular use of intraoperative autotransfusion is more effective than selective use.

Blood Transfusion↗

PubMed1980

Afterload reduction with hydralazine following valve replacement.

Impedance reduction with hydralazine was evaluated in 23 patients 1 to 3 hours after aortic or mitral valve replacement. Patients were randomly assigned to Group 1 (0.25 mg/kg) or Group 2 (0.5 mg/kg) and responses at 20, 60, and 120 minutes compared with control (paired t test) and mean values for each group compared (t test). In Group 1 significant responses were the fall in mean arterial pressure (78.3 +/- 3.0 to 66.7 +/- 2.2 mm Hg) and systemic vascular resistance (2,808 +/- 264 to 1,823 +/- 164 dynes-sec/cm5); the increase in cardiac index (2.07 +/- 0.13 to 2.71 +/- 0.21 L/min/m2), stroke volume index (26.9 +/- 2.3 to 34.0 +/- 3.3 ml/beat), and heart rate (80.8 +/- 5.8 to 84.2 +/- 6.6 beats/min). Central venous pressure did not change and left atrial pressure decreased at 120 minutes. Group 2 responses were similar except for higher central venous pressure at 20 minutes, higher left atrial pressures at control, 20, and 60 minutes, and lower left ventricular stroke work at control, 20, and 60 minutes. By selectively dilating the arterial system, hydralazine reduces mean arterial pressure and systemic vascular resistance and increases cardiac output with suble filling pressures.

Aortic Valve↗

PubMed1977

Pulmonary and left atrial hemodynamics in mital stenosis.

A laboratory model has been utilized to evaluate left atrial and pulmoanry hemodynamics while comparing atria of three different compliances, five valve orifices, four pulmonary complicances, two venous pressures, and a predetermined pulmonary vascular resistance. The data demonstrate significant relationships between these variables and cardiac output, pulmonary artery pressure, and left atrial pressure and between the variables themselves. The complexity of these interrelationships is consistent with the lack of simple linear relations between current clinical measurements and emphasizes the need for measurements of compliance if the hemodynamic consequences of mitral stenosis are to be better understood.

Blood Pressure↗

PubMed1977

Topical cardiac hypothermia and phrenic nerve injury.

The relationship between ice-chip cardioplegia and impaired left diaphragmatic function was evaluated in dogs. Direct or indirect contact of the phrenic nerve with crushed ice for 30 or 60 minutes resulted in phrenic paralysis for 6 to 28 days, with responsiveness returning from 7 to 62 days later. Microscopical examination of injured nerves revealed injury to the myelin sheath and preservation of axons. Paralysis of the left diaphragm after topical cardiac hypothermia may be secondary to cold injury of the phrenic nerve, which is reversible.

Animals↗

PubMed1977

Coronary venous arterialization: acute hemodynamic, metabolic, and chronic anatomical observations.

Nine dogs that had anastomosis of the internal mammary artery (IMA) to the left anterior descending coronary vein (LADV) were studied acutely on right-heart bypass. Occlusion of the left anterior descending coronary artery (LADA) and LADV without venous arterialization resulted in a significant decline in stroke work, total coronary flow, and myocardial oxygen uptake; with reactive hyperemia an increase in lactate and pyruvate consumption resulted. Occlusion of the LADA and LADV with VA did not change these variables greatly, except for a marked increase in total coronary flow with reactive hyperemia. Chronic venous arterialization in 14 dogs was associated with a 14% mortality, while 10 controls had a 40% mortality. Dogs were killed at six weeks, and prior angiography in 9 showed patency of the IMA to the heart without filling of cardiac veins. All dogs had infarcts in the distribution of the LADA; these infarcts were smaller in dogs with venous arterialization. The anastomoses were obliterated by mature or maturing fibrous tissue, with alteration of the vein so that it was frequently not discernible, while the IMA was well preserved. Distal veins had foci of intimal proliferation, subintimal fibrosis, and medial hypertrophy. Although venous arterialzaiton provides protection for the acutely ischemic myocardium, this effect does not persist, perhaps because of anastomotic occlusion due to fibrous proliferation.

Animals↗

PubMed1977

Aortic venting. Comparison of vent effectiveness.

Three commercially available aortic vents have been evaluated as to effectiveness in removing small volumes of air introduced into a mock circulatory circuit. Without aspiration, Vent 2 was the most effective and removed 58 per cent of 0.1 ml., 90 per cent of 0.5 ml., and 74 per cent of 1.0 ml. boluses at a cardiac output of 2 L. At a cardiac output of 4 L., Vent 2 removed 42, 76, and 49 per cent, respectively. With aspiration (Vent 2 not designed for aspiration) and a 2 L. cardiac output, Vents 1 and 3 removed 84 to 98 per cent of 0.1 ml., 68 to 92 per cent of 0.5 ml., and 74 to 86 per cent of 1.0 ml. boluses. With aspiration and a 4 L. cardiac output, Vent 3 was significantly more effective than Vent 1 and removed 92 to 94 per cent of 0.1 ml., 82 to 86 per cent of 0.5 ml., and 77 to 80 per cent of 1.0 ml. boluses. One liter of canine blood was aspirated through Vents 1 and 3 and a flow rate of 250 ml. per minute. For Vent 1, serum hemoglobin levels increased from 40 to 249 mg. per 100 ml. and for Vent 3 from 49 to 212 mg. per 100 ml. There are significant differences in the ability of commercially available aortic vents to remove small air bubbles trapped in the heart after initial direct cardiac venting. Vents having the capability of aspiration are more effective and result in acceptable hemolysis.

Aorta↗

PubMed1976

Left ventricular aneurysmectomy.

Comparison of preoperative and postoperative studies in 81 patients undergoing left ventricular aneurysmectomy failed to show consistent hemodynamic trends. The most reliable prognostic indicator for survival (84% early, 71% late) was the function of the basilar ventricular segments. In 62 of the 81 patients, there was concomitant aortocoronary bypass grafting. Eighty-eight percent of the surviving patients are essentially free of symptoms. These findings support the continued surgical treatment of ventricular aneurysm in symptomatic patients, and suggest nonoperative treatment for patients who are asymptomatic.

Coronary Artery Bypass↗

PubMed1976

Intraaortic balloon assistance.

Intraaortic balloon (IAB) assistance in 64 patients over 2 1/2 years has resulted in a survival rate of 11% (1 patient) when used alone but 47% when utilized in patients treated surgically (long-term survival, 38% [21 patients]). Patients undergoing coronary artery bypass grafting or aortic valve replacement have a long-term survival of 50% (8 and 9 patients, respectively). The required duration of IAB support has a bearing on the clinical result. Complications have been minimal. Though it was originally developed to assist in the nonoperative management of complications of ischemic heart disease, IAB assistance offers significant promise as an adjuvant to operative therapy for both ischemic and valvular heart disease.

Aortic Valve↗

PubMed1976

In favor of the Y-graft for aortocoronary bypass.

The technique of multiple coronary artery bypass grafting has included separate conduits, snake grafts, and Y-grafts. Against the Y-graft have been reports of lesser patency and several theoretical objections. The theory is discussed and a laboratory model presented which demonstrates a flow difference of 2 ml/5 sec or less between Y-grafts and single grafts. In conjunction with this, 171 patients having aortocoronary bypass were analyzed and showed a combined one-year graft patency of 77% with no significant difference between single grafts and Y-grafts. It is concluded that the technical simplicity of Y-grafts is advantageous and that, if the operation is performed within the guidelines set forth, revascularization with Y-grafts is an acceptable method.

Animals↗

PubMed1976

A servocontrolled atrial-aortic assist device: experimental findings and clinical experience.

A servocontrol system was developed to regulate a single roller pump left atrial-aortic (La-A) assist device. Responsiveness of the servomechanism to blood volume changes, myocardial damage, and mitral regurgitation was evaluated in 5 sheep and 6 dogs. Myocardial damage was induced by occlusion of coronary arteries. and the hemodynamic effects of La-A assistance were evaluated. While La-A assistance reduced left atrial pressures to low levels, the left ventricular end-diastolic pressure remained elevated in the severely damaged heart. LaA-assistance was used in 3 patients. Two were weaned from cardiopulmonary bypass after failure of intraaortic balloon counterpulsation, and 1 is a long-term survivor. The third was supported for 48 hours after attempt repair of complex congenital heart disease. The servocontrol device added to the safety of prolonged La-A assistance. This mode of assistance should be considered when intraaortic balloon counterpulsation has failed.

Adolescent↗

PubMed1976

Operative flow measurements and coronary bypass graft patency.

Early (one week) and late (one year) postoperative angiography was performed in 142 patients having 310 grafts (117 right coronary artery [RCA], 134 left anterior descending [LAD], and 59 circumflex coronary artery [CCA]) to assess the factors responsible for failure of aorta-coronary artery saphenous vein grafts. Early catheterization revealed an 85.5 per cent patency rate with similar rates for each artery (RCA 88 per cent, LAD 85 per cent, and CCA 81 per cent). At one year 238 grafts remained patent, for a cumulative patency rate of 76.8 per cent with a similar distribution for each vessel (RCA 75 per cent, LAD 78 per cent, and CCA 76 per cent). Intraoperative flow measurements were correlated with early and late patency. Grafts with a basal flow less than 20 ml. per minute have a 42 per cent early closure rate and a 21 per cent late closure rate (cumulative 63 per cent). A basal flow of less than 40 ml. per minute was associated with a 25 per cent early failure and an 11 per cent late failure rate (cumulative 36 per cent). Basal flow at levels greater than 40 ml. per minute was not associated with an increased probability of graft closure. Absence of reactive hyperemia (30 second graft occlusion) was associated with a 19 per cent probability of early closure and a 31 per cent probability of cumulative thrombosis. A papaverine-induced flow increase (15 mg. given into the graft) of less than 100 per cent over basal flow gave a 20 per cent probability of early failure and 30 per cent probability of cumulative closure. Thus intraoperative basal flow measurements are of predictive value in determining the fate of aorta-coronary artery vein bypass grafts, and vasodilatory maneuvers provide little additional information.

Coronary Artery Bypass↗

PubMed1975

Implantable pacemakers in children.

Permanent pacemakers were implanted in 12 children, ages 2 weeks to 6 years. The cause of the arrhythmia was congenital in three, postoperative in six, viral in one, and unknown in two. One operative death occurred on the second postoperative day. Two late deaths occurred five and 10-1/2 years postoperatively. The late deaths were in patients with good cardiac capture in whom the block followed repair of tetralogy of Fallot. Ventricular arrhythmias were believed to be the cause of death. Reoperation was required 37 times: for pacemaker exhaustion, 17; electrode problems, 15; wound problems, four; and arrhythmia, one. Nine of 12 patients are alive nine months to ten years eight months postoperatively. The remaining three survived for eight to ten years. Frequent reoperation and dilligent correction of defective pacing is rewarded with long, active lives in children requiring implantable pacemakers.

Adolescent↗